Conchodytes nipponensis (De Haan, 1844), a caridean shrimp living in the mantle cavity of a pen shell (Atrina pectinata) is reported for the first time from Korea. It was collected from a depth of 15 m depth. Its morphology is described and illustrated, and a color image of a living specimen is provided. This is at the same time the first record of the genus Conchodytes, and the first record of a bivalve mollucs associated shrimp, from Korea.